Members Page/Desurq - VEMS wiki www.vems.hu

MembersPage/Desurq (2016-07-21 10:07:01)

Returning Vems ECU v3/1441 for test and repair for the second time. This ecu was sent back a few weeks ago for test. The ecu is used on an audi UR Quattro with ABY style loom and engine. The ECU has the following problems => Gut replacement because of 3d issue

1. There is no cam-hall inverter. PLEASE fit cam hall inverter.

there is no provision for cam-HALL inverter on those old devices. (so it's addon, and it can be fitted externally) Do you really need it ? Why ? It should not matter (only config is slightly different, it does not normally have any significance) Are you using a 7A flywheel that has "noisy crankhome-VR" ?
- after gut replacement new ECU will have cam-HALL inverter anyway by default, OK.

2. The ecu is setup for a 1.8T Inlet air temperature sensor. PLEASE add strong MAT pullup for a standard (PTC type) ABY MAT sensor.

btw, would be easy on site: Add an 510 Ohm pullup resistor between +5V and MAT input (or 240 Ohm if tapping EC36/29 for +5V, which has 270 Ohm inside internally already. Don't use EC36/29 for any other load - such as TPS - than).
- of course new ECU made for PTC strong MAT pullup

3. The next problem is a major one. This ecu seems to “crash” when the ignition is turned on some times. It can be ok for a few days and then crash twice in a row. What happens is that when the ignition is turned on normally the fuel pump runs for 1-2 seconds and this is normal. When the ECU “crashes” the fuel pump will sometimes not run at all , or run constantly. When this happens I cannot access the ecu with Vems tune. The only way to recover the ECU is to force the ECU into bootloader by joining pins 2-3 on the RS232 connection. Then I upload the firmware and the config and all is ok for a time again. This can leave the car stuck when it happens and the laptop battery is low. I have tried checking ALL connections and especially power and ground, and made some new connections via a new relay but still the problems exist. As this fault is temperamental and intermittent, if a fault cannot be found then I would like a complete new main board installed. I have another VEMS ecu and it does not give this problem when connected to this car.

4. The wideband lambda would not work on 2 known good sensors. I had used an ignition feed from the same relay that powers the ECU to feed the wideband as the diagram shows, but it wouldn’t work until I also connected 12v to the ecu VIA the wideband pin on the ecu wideband plug. Is this normal? Problem 3 above only started I think once I did this to make the wideband to work.

Weird indeed

As you can see I have had many problems with this ECU and need the ECU to be returned ASAP fully tested and with all the above faults and problems resolved.

Thanks Des.